Researchers argue that women are less likely to engage in bribery than men. However, it is unclear which underlying formal or informal norms shape the relationship between gender and corruption activities, especially in the private sector. This research investigates whether and why business women differ from businessmen in the probability of bribing. Using the China Micro and Small Enterprise Survey in 2015, I argue that (1) female business owners bribe significantly less often than their male counterparts; (2) formal institutional norms do not significantly mediate gender and corruption activities; and (3) informal social norms, e.g., business women being less aggressive and expansive, significantly mediate gender’s impact on firms’ corruption. This chapter thus questions the role of formal institutions in fostering gender differences in corruption. It also sheds light on the role of informal gender norms in influencing business owners’ bribery activities.